Fiber optic cables are widely used for data transmission and require careful handling because of the fragile optical fibers being carried and protected by such cables. These cables are suspended from support structures via support devices and are subject to various dynamic and static stresses that must be controlled. Static stress is caused primarily because the cable is suspended only at longitudinally distanced points while dynamic stress is caused mainly by oscillation of the cable. This oscillation, generally resulting from wind, ice and varying temperatures affecting tension of the cable can damage the cable and associated fibers. Many support devices do not adequately control the effect that stresses have on the cable. For instance, the support device must permit a limited amount of oscillation but not so much as to cause damage to the fibers.
Nor do many of the support devices facilitate ease of stringing the cable. Along with supporting the cable, the device must accommodate the required sag of the cable between support structures. Also, the device must allow cable to slip before fiber damage occurs, yet maintain the cable to required installation tensions. Typically the devices require disassembly, have many parts and do not reassemble easily. As the cables are strung and repaired in the field where non-optimal conditions are almost a certainty, a device that allows for quick and easy stringing of the cable is desired.
Further, many of the support devices do not easily attach to the designated support structure. For example, U.S. Pat. No. 5,014,941 ('941) discloses a fiber optic cable support assembly that includes two body portions providing a central bore. An internally threaded aperture in one body portion permits the assembly to be attached to a structure having a pre-embedded fastener, although the body portion must be rotated to attach the assembly to a support structure. Obviously this rotation precludes stringing the cable until after the device is attached to the structure and over all complicates the installation of the assembly. Also, this device includes several loose parts that must be maintained during installation.
U.S. Pat. No. 5,435,507 ('507) also discloses a cable support Typically, the '507 device is used for low tension, short span applications that utilize small diameter cable. Although this device overcomes some of the problems associated with the '941 device, it has its own inherent shortcomings. The device must be secured to a support structure via a bolt. That is, the bolt is embedded into the support structure such as a pole, and an associated nut is tightened. Also, the device uses a capturing feature for the head of the mounting bolt which limits the type of fastener that can be used to secure the device. Further, the device provides gains that are intended to bite into and grip the support structure. Thus, the device can not be used on a support structure that can not receive a bolt or accommodate these gains. Even if the device could somehow be secured to a support structure absent the use of the bolt, the gains would severely weaken the contact achievable between the device and the support structure. Like the '941 device, this device has loose parts that must be maintained during installation. Also, the device employs a cushion that the installer must correctly wrap around the cable.